Control switch



March 4, 19 30.

c. E BOGGS CONTROL SWITCH Original Filed AprillO. 1926 3 Sheets-Sheet lWITNESSES C. E. BOGGS CONTROL SWITCH March 4, 1930.

Original Filed Aprii 10, 1926 3 Sheets-Sheet INVENTOR WITNESSES March 4,1930. I c E BOGGS -i,749,6 93

CONTROL SWITCH Original Filed April 10, 1926 3 Sheets-Sheet 3 Patented4, 1930 UNITED STATES PATENT OFFICE COMPANY, INC., A. CORPORATION OF NEWYORK coNrBoL swrrcn Original application filed April 10, 1926, SerialNo. 101,150. Divided and this application filed Qctober 5,

' 1926. Serial No. 189,629. Renewed December 4, 1929.

This invention relates to thermostatic switches for use in heatingsystems or the like, and the present application is a division of anapplication bearing Serial No. 101,150, filed April 10, .1926, entitledElectric heating system.

It is among the objects ofthis invention to provide a thermostaticswitch which shall be adapted to automatically regulate the flow ofcurrent in a plurality of connected heatin units to so correlate thefunction of such units as to render them severally operative and whichshall function automatically to cut off one of said units from thecommon power circuit while the other of said units is operative.

Another object of this invention is to provide a thermostatic switchwhich shall function to control the temperature of one of the heatingunits with which it is electrically connected independently of itscooperative function with the other of said units.

Another object of this invention is to pro vide a combination relay andthermal switch of the above designated character which shall comprise aminimum number of operating parts contained in a housing to constitute asimple, compact unit for application to electric heating systems.

Where electric cooking ranges are emloyed for domest1c use an electricwater eater is found to be a necessary adjunct on account of theelimination of the coal or gas fire range with its water heating coils.My.

invention is particularly applicable for use in electric range andwater-heating systems,

' using three-wire circuits, to provide regulation of the load upon theindividual customers service wires. a j

on account of the heat storingcharacteristics of water, electric energyfor water I heaters may be utilized at a time when there is no demandfor energy for cooking pur poses, and in accordance with my presentinvention' I Y rovide a thermostatic switch which shall be adapted tofunction as a combination range and water heater alternatingswitch orrelay and a water heater thermal switch, thus making t loadcharacteristics of heating systeigs in w a range and wapropertemperature.

ter heater are connected controllable by antomatic re ulation to theextent of making the water respect to the range load.

My thermostatic switch is also adapted to eating an oii peak load withfunction as a thermal switch for water heat- 5 ers to automatically openthe water heater circuit when the temperature of the water has reached apredetermined maximum and to automaticallyclose the circuit when thetemperature has dropped. The thermostatic switch functioning as athermal unit effects a great saving of energy not only in the preventionof waste by the boiling of the water but also in its automaticregulation of the water heater to consume no more energythan isnecessary for maintaining the water at a In accordance with the presentinvention the thermostatic switch may be employed as an alternatingswitch or relay as hereinabove set forth, or. as a water heater thermalswitch or both, as will be hereinafter more fully set forth inconnection with a detailed description of the drawings.

In the accompanying drawings constituting a part hereof in which likereference characters designate like-parts. Fig. 1 isja. view inperspective of a thermostatic switch embodying the principles of myinvention,

together with a diagram illustrating its con-' "and Fig. 5 is anelevational view of the temperature control actuating member by means ofwhich the several cooperating elements of the switch mechanism areoperated.

Referring to Fig. 1 of the drawings the structure therein illustratedcomprises a bimetallic bar 1 of spiral shape fastened in the manner of aclock spring by securingone end thereof-to an adjustable member in the 5and having its other end secured to sha casing or housing member. 2,asshown in Fig 3, Figs. 1 and 5, which is actuated by the spiral bar 1in accordance with temperature changes to which the latter is subjected.

On the end of the shaft 3 there is provided an insulating disk 4 securedto a bushing 5 of insulating material which is adapted to rotate withthe shaft 3 and a pair of mercury switches 6 and 7 of the tilting typeare secured to the disk 4 b spring cl' 5 8 shown in Fig. 2. The switc es6 an are connected to binding posts 9 and I'Oand 11 and 12,respectively, as shown ,in Fig. 3, these posts being in turn connectedto terminals 13 and 14 and 15 and 16, respectively, as shown in Fig. 1,the terminals 13 and 14, 15 and 16 being respectively connected byflexible leads 17 to stationary terminals 18, 19, 20 and 21.

A resistor element 25, Fig. 2, is mounted adjacent the spiralbi-metallic member 1 between conductors 26 secured to the stationaryterminals 20 and 21 which as previously explained are connected to theterminals of the tilting switch 7 which when closed constitutes aby-pass or shunt on the resistor 25. A shunt gap comprising a pair ofcontact elements 28 and 29 is provided on the ferrules 30 of the switch7 and a high resistance wire 31 is inserted therebetween for the purposeas will be hereinafter set forth.

Referring to Figs. 2, 3, 4 and 5, the housing member 2 comprises acasing 35 having a partition or wall 36 extending therethrough toprovide a thermal chamber in which the spiral member 1 and the resistorelement 25 are disposed. The end of the casing35 is provided with aflanged rtion 37 which constitutes a bearing for t e sleeve 5 which issecured to rotate with the shaft 3 and on which is mounted theinsulating disk 4. A glass cover 38 is adapted to be fastened on thecasing 35 by a plurality of wing nuts 39 which interact with thethreaded portion of posts 40 extendin from the casing 35, thusconstituting the thermostatic switch a compact self-contained unit.

For the purpose of adjusting the spiral member 1 to actuate the shaftmember 3 at certain desired temperatures within the thermal chamber Ihave provided an adjusting device comprising a gear rack 41 secured tothe end of the spiral bar 1 and cooperatively engaged with a pinion 42that meshes with a ar 43 mounted on a shaft 44 extendin ongitudinally ofthe housing member beyon the glass case 38, the member 44 being providedvrfth a knob 45 to rotate the same. A graduated disk or dial 46 issecured to r0 tate with the shaft 44 to indicate the adjustment in termsof degrees of temperature or other suitable markings. The gear and shaftof the adjusting mechanism are respectively journaled to rotate in thecasing by means of 'a projecting bracket member 47 shown in Fig. 2. Thethermal unit may be secured at 1.74.9,ees

its base 48 to a switch board or to the wall 49 of a water heater sothat the spiral member 1 is responsive to the temperature changes withinthe water heater or the heat of the resistor element 25 or both for thepurpose as willbe hereinafter set forth.

As shown in Fig. 4 the stationary contacts 18, 19, 20 and 21 areconnected by terminal leads 50, 51, 52 and 53 which extend throughinsulating bushin 54 to the outside ofthe housing for electricallyconnectingthe thermostatic switch in a circuit as shown in Fig. 1.

Referring to Fig. 1, the thermostatic switch together with a waterheater 57 and a range 58, whose operation it is adapted to control, areshown connected to a three-wire source of current supply in circuitrelation with a main switch 55 and meters 56. The water heater 57 isconnected in series across the outer legs of the circuit and tothetermipals 18 and 19 which are connected to the tilting switch 6. Theresistor element is connected to the terminals 20 and 21 which are inseries with the neutral leg between the entrance switch and range. Theterminals 20 and 21 are connected to the terminals 15 and 16 of thetilting switch 7 as previously explained.

- The operation of this device is briefly as follows: r i

The spiral member 1 is adjusted so that the shaft 3 with which it isconnected will be actuated at .a certain temperature thereby tilting themercury switch 6 breaking the circuit across its terminals and openingthe water heater circuit. This function may be brought about in twoways, namely, by the temperature rise of the water in the heater if thethermostatic switch unit is mounted with its base 48 secured to theheater wall 49 as shown in Fig. 2, orb .the unbalanced load in theneutral leg of t e range circuit which is connected to the resistorelement 25. a In the latter occurrence the rotating of the disk 4 willtilt the switch 6 and open the water heater circuit the same as when theshaft 3 is actemperature rise in the water of the heater. If when thewater heater circuit is opened the unbalanced load in the neutral of therange increases, the heat of the resistor 25 will in. crease, resultingin an increased rotation of tuated when the member 1 is responsive tothe shaft 3, thereby tilting the switch 7 to a position where themercury will establish a circuit across its terminals forming a bypassor shunt on the resistor 25, thus reducin the heat generated in theresistor to zero. I the resistor element 25 should be burned out ordamaged in anyway the current will pass acrom the constituted b thecontacts 28 and 29 an t rough the hig resistance wire 31 which will beburned out to allow the gap to close thereby establishing a shunt acrossthe resistor.

- When the range 58 is deenergized the heat in the thermal chamber willdrop by radiation and convection so that when the temperature in thethermal chamber again reaches normal the shaft 3 will tilt the switchesin the reverse direction to again close the water heater circuit. Ifduring the operation of the range the temperature of the thermal chamberdrops thereby actuating the shaft 3 the mercury switch 7 willbe tiltedto open the shunt across the resistor 25 which will be rapidly heated bythe unbalanced load current to prevent the further rotation 'of theshaft thereby preventing the closing of the water heater switch 6, theswitches being so mounted on their common supporting disk 4 that theywill operate at a sufficient time lag to regulate the water heater andrange circuits as explained. The total rotative or angular movement ofthe disk 4 through which the mercury switches operate is approximatelysixty degrees.

Where it is intended to utilize the device as a thermal switch only forwater heaters, but one mercury switch is necessary since the by-pass orshunt switch 7 and the resistor member 25 with which it is connectedneed not be utilized. In this manner the switch would be set to trip atany desired temperature and would automatically close again when thetemperature in the thermal chamber falls.

The by-pass switch 7 must be employed when the thermostatic switch isused as a range-water heater alternating switch on account of the largevariation in the heat generated in the resistor element in accordancewith the change of the unbalanced load in the range neutralcorresponding to the capacity of the ran e which is ordinarily rated ata maximum un alanced load of 3000 watts. Since the energy consumed bythe resistor member varies as the square of the current flowing in therange neutral, it will be seen that the heat generated at 1000 wattswill be one-ninth of that generated at 3000 watts so that the by-passfunctions to prevent a dangerous rise at full load. Connecting theresistor element in the neutral leg of a three-wire range circuit forpick -1ng up. energy to operate a range water heater. alternating switchis a novel expedlent and provides a ratio between the desired trippingcurrent and the total current to be handled by the device twice as greatas when the two outside legs of the circuit are utilized. Otheradvantages are that but a single circuit is required instead of two towire the thermostatic switch from the range circuit and since thepotential of a neutral circuit is zero with respect to the ground theinsulation difficulties in the switch unit and danger of accidental,short-circuits therein are materially reduced.

It is evident from the foregoing description of my invention that athermostatic switch unit made in accordance therewith provides a simpleand eificient combination range and water alternatingswitch or relay andsimultaneously or independently functions as a water heater thermalswitch. By the use of my device a great saving of electrical energy iseffected and the matter of regulating the water-heater and range loadsis automatically and positively accomplished. My device functionin as awater heater thermal switch alsoehminates the fire hazards incidental towater heaters of large capacity. 1

Although I have described several embodiments of my invention it will beobvious to those skilled in the art that various modifications may bemade in the details of constructionand in the adaptation of my inventionfor other uses without departing from the principles herein set forth,for instance, the water heater may be connected between the neutral andoutside leg of the heating circuit, in other words a 110 volt as well asa 220 volt water heater maybe employed.

I claim:

1. A thermostatic switch comprising a bimetallic bar, an operating shaftsecured to and adapted to be actuated by said bar, a plurality ofmercury switches associated with and adapted to operate with themovement of said shaft, and a resistor element mounted adjacent saidbar, said mercury switches being adapted for operation by the actuatingcharacteristics of said bar responsive to the heat variations of saidresistor element and one of said switches constituting a by-pass on saidresistor element.

2. A thermostatic switch comprising a bimetallic bar, an operating shaftsecured to and adapted to be actuated by said bar, a plurality ofmercury switches associated with and adapted to operate with themovement of said shaft, and a resistor element mounted adjacent said barto heat the same, one of said mercury switches being adapted toautomatically control a heating circuit and the other of said switchesfunctions as a by-pass or shunt on said resistor element. v

3. A thermostatic switch comprising a bimetallic bar, an operating shaftsecured to and adapted to be actuated by said bar, a pair of mercuryswitches mounted for tilting movement on said shaft, a resistor elementmounted adjacent said bar and having an electrical connection with oneof said mercury switches, and a gap connected acrossv said resistor andadapted to close at a predetermined temperature of the latter.

4. A thermostatic switch comprising a housing member having a partitionto provide a thermal chamber, a bi-metallie bar disposed within saidchamber and secured at one end to the housing member, a shaft journaledfor rotation in said housing and secured to said bar, a disk mounted onsaid -shaft outside of said chamber, a pair of mercury switches securedto said disk, a resistor clement mounted in the thermal chamber adjacentsaid spiral bar, and connected to one of said switches. and terminalleads extending through aid housing and connected to said swit hcs.

5. A thermostatic switch comprising a housing member having a partitionto'proride thermal chamber, a bi-metallic bar disposed within saidchamber and secured at one end to the housing member, a shaft journalledfor rotation in said housing and se- 'curcd to said bar, a disk mountedon said shaft outside of said chamber, a air of mercury switches securedto said dis a resistor element mounted in the thermal chamber adiacentsaid spiral bar and having an electrical connection with one ofsaid switches, a

gap connected across said resistor element, and terminal? leadsextending through said housing andlconnected to said switches.

6. A thermostatic switch comprising a housing member having a partitionto provide a thermal chamber, a bi-metallic bar disposed within saidchamber and adjustably secured at one end to the housing member, ashaftjournaled for rotation in said housing and secured to said bar, a diskmounted on said shaft outside of said chamber, a pair of mercuryswitches secured to said disk, a resistor element mounted in the thermalchamber adjacent said bar and connected to one of said switches,'andmeans for adjusting-the-bar to be responsive to any desired temperaturein the thermal chamber.

7. A thermostatic switch comprising a housing having a thermal chamberdisposed in it, a movable member rotatably mounted duced when a circuitis. established through said heating element, ani: means adapted toconnect one of the switches mounted on the movable member in shuntcircuit relation with the heating element to short circuit it when itstemperature exceeds a predetermined limit.

In testimony whereof, I sign my name. CLARENCE E. BOGGS.

in said housing, a plurality of mercury 4o switches mounted on saidmember, a bimetallic bar disposed within said chamber and o erablycoupled to said movable member, said bimetallic bar being adapted toeffect the movement of said mercury switches in response to the normaltemperature conditions in the chamber, a resistor element mounted insaid chamber adjacent said bar, said resister element being adapted tobe connected in an electric circuit to efiect the movement of saidmercury switches when a circuit is established through it, and means forconnecting one of said mercury switches in shunt circuit relation withsaid resistor to short circuit the resistor if the resistor gets toohot.

8. A thermostatic switch comprising a movably iounted member having aluralit of switches mounted thereon, a ermal ciement operably coupled tosaid movable response to the normal temperar'e -:01'2Cliti0nssurrounding said element, a heating element arranged adjacent saidthermal element and adapted to be connected in an electrics-T ircuit forrendering said switch responsive to the temperature conditions proandadapted to effect the movement

